canvas in w3schools code example
Example 1: javascript canvas
<canvas id="canvas"></canvas>
<script>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.beginPath();
ctx.rect(x, y, width, height);
ctx.fillStyle = 'limegreen';
ctx.fill();
ctx.beginPath();
ctx.arc(x, y, radius, startAngle, endAngle, counterClockWise(optional));
ctx.strokeStyle = 'black';
ctx.stroke();
</script>
Example 2: javascritp canvas
//Creates a canvas and draws a circle
var canvas = document.body.appendChild(document.createElement("canvas"));
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.arc(canvas.width / 2, canvas.height / 2, 50, 0, Math.PI * 2);
ctx.fillStyle = "red";
ctx.strokeStyle = "black";
ctx.stroke();
ctx.fill();